The authors describe a case of paradoxical bronchospasm with laryngospasm and cutaneous rash occurring in an asthmatic woman after the use, via metered-dose inhaler, of different bronchodilators containing soy-derived excipients. It is noteworthy that the patient was not affected by soy allergy. After a short review of the relevant literature, the authors consider the possible aetiopathogenetic factors and outline the importance of this rare adverse reaction in the care of asthmatic patients.